On Fri, 2012-04-06 at 17:57 +0530, Santosh Y wrote:
> Currently the Expected data transfer length field in
> command UPIU is being updated with "transfersize" from
> the scsi_cmnd struct. But, if the read/write data
> transfer size exceeds the sector size, the "transfersize"
> will be truncated to the sector size. Thanks to KOBAYASHI
> Yoshitake for pointing it out.
I'm a bit confused by this changelog, but I think it's saying you're
using the cmd->transfersize field for the length of data to transfer?
In which case, that's wrong cmd->transfersize is the minimum transfer
size (usually a sector) ... badly named field, sorry.
Based on the calculation below, the actual length you're looking for is
scsi_cmnd->sdb->length
Which is the total size of the entire transfer in bytes.
> This patch ensures that the correct read/write data transfer
> size is calculated from the "transfer length" available in the
> CDB.
>
> Reported-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@xxxxxxxxxxxxx>
> Reviewed-by: Vinayak Holikatti <vinholikatti@xxxxxxxxx>
> Signed-off-by: Santosh Y <santoshsy@xxxxxxxxx>
> ---
> drivers/scsi/ufs/ufshcd.c | 37 ++++++++++++++++++++++++++++++++++++-
> 1 files changed, 36 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 1878cd8..4f99ab4 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -585,6 +585,41 @@ static void ufshcd_int_config(struct ufs_hba *hba, u32 option)
> }
>
> /**
> + * ufshcd_get_transfer_len - calculate data transfer size for read/write
> + * commands from the CDB
> + * @cmdp: pointer to SCSI command
> + */
> +static inline u32 ufshcd_get_transfer_len(struct scsi_cmnd *cmdp)
> +{
> + u32 transfer_len;
> +
> + switch (cmdp->cmnd[0]) {
> + case READ_6:
> + case WRITE_6:
> + transfer_len = cmdp->device->sector_size *
> + cmdp->cmnd[4];
Just an efficiency not here, even though the code won't be written this
way, you don't want to multiply by sector_size ... it's always a power
of two, so you do shift or binary log tricks to avoid the expensive
multiply.
James
> + break;
> + case READ_10:
> + case WRITE_10:
> + transfer_len = cmdp->device->sector_size *
> + ((cmdp->cmnd[7] << 8) |
> + cmdp->cmnd[8]);
> + break;
> + case READ_16:
> + case WRITE_16:
> + transfer_len = cmdp->device->sector_size *
> + ((cmdp->cmnd[10] << 24) |
> + (cmdp->cmnd[11] << 16) |
> + (cmdp->cmnd[12] << 8) |
> + cmdp->cmnd[13]);
> + break;
> + default:
> + transfer_len = cmdp->transfersize;
> + }
> + return transfer_len;
> +}
> +
> +/**
> * ufshcd_compose_upiu - form UFS Protocol Information Unit(UPIU)
> * @lrb - pointer to local reference block
> */
> @@ -640,7 +675,7 @@ static void ufshcd_compose_upiu(struct ufshcd_lrb *lrbp)
> ucd_cmd_ptr->header.dword_2 = 0;
>
> ucd_cmd_ptr->exp_data_transfer_len =
> - cpu_to_be32(lrbp->cmd->transfersize);
> + cpu_to_be32(ufshcd_get_transfer_len(lrbp->cmd));
>
> memcpy(ucd_cmd_ptr->cdb,
> lrbp->cmd->cmnd,
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